The present invention relates generally to the field of integrated circuits and more particularly to a programmable gate array device.
Single metal mask programmable gate arrays typically have combinatorial blocks that use a first metal layer to form the basic electrical connections of the combinatorial blocks. In addition, the first metal commonly has a plurality of metal cross connects. The metal cross connects provide the basic interconnectivity of the gate array device. The programmable metal mask layer is then used to provide the customized connections that define the device for a particular function. Unfortunately, the metal cross connects take up valuable space that cannot be used for circuitry. This wastes silicon wafer space and limits the circuitry that can be placed on the integrated circuit.
Thus there exists a need for a programmable gate array device that overcomes these and other problems.
A programmable gate array device that overcomes these and other problems has a repeating block of circuitry that includes a lower metal layer. The repeating block of circuitry includes a row of combinatorial blocks. A number of metal segments run perpendicular to the row of combinatorial blocks. The metal segments are formed in a middle metal layer. A customizable metal layer forms a top metal layer.